Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description must carry the burden of behavioral disclosure. It only states what the tool returns, without mentioning any safety traits (e.g., read-only), potential errors, rate limits, or other behavioral aspects. For a read-only query, this is minimal transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, concise sentence that is front-loaded with the main purpose. It contains no unnecessary words and efficiently conveys the tool's functionality.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity (two parameters, no output schema), the description is fairly complete. It covers the core functionality and parameter usage. It does not describe the return format or error conditions, but for a balance query, these are not critical omissions.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. The description adds meaning by explicitly stating that tokenAddress is optional and that omitting it fetches the native balance, which clarifies the parameter's role beyond the schema descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it returns the native FUSE balance or an ERC-20 token balance for an address. It uses a specific verb 'returns' and identifies the resource 'balance'. It distinguishes between native and token balances via the optional tokenAddress parameter, which differentiates it from sibling tools that perform other operations.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when to use the tool (to get a balance), but it does not explicitly state when not to use it or mention alternatives among the many sibling tools. However, the purpose is clear enough that an agent can infer this is the appropriate tool for balance queries.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.